The present invention relates to devices for extinguishing oil well fires and, in particular, to a steerable assembly including means for collapsing the casing.
The inherent risk in owning and operating a producing oil well is the danger of a fire starting at the wellhead. Such fires are extremely difficult to extinguish due to the presence of high pressure flammable liquids and vapors which are emitted from the well. Even if temporarily extinguished, the high pressures can re-supply flammables to sustain the fire. That is, the presence of heated metal and other debris in the vicinity can exceed the flashpoint of the flammables and can restart a fire. The pressures also present difficulties in containing the flames, if attempting to cap the fire.
Further difficulties can arise depending upon the location of the rupture and type of rupture. The rupture may occur either above or below the ground and affect the ability to gain access. The rupture may also consist of a split verses a clean break. Debris or other devices, such as explosive mines, in the case of fires started in the aftermath of the Persian Gulf War, may also limit access. The manner of extinguishing a fire may therefore have to be adjusted to the prevailing circumstances.
One known method for fighting such fires is to explode explosives in close proximity to the source of the fire to evacuate the area of oxygen, upon detonation, and thereby extinguish the fire. Another method is to directly cap the wellhead in the manner of dousing a candle. Still another is to use refrigerants to reduce the flashpoint in proximity to the wellhead.
Otherwise, Applicant is unaware of any efforts directed to physically pinching-off the well casing and thereby separating the fuel source from the fire.